How often to do water changes in a heavily planted tropical tank?

[kieran01pd2016]

I'm new to the scene and have a 180L long boy that's heavily planted, mainly with brazilian pennywort and pearl weed. Both of which are growing like mad and the pennywort is starting to come out of the tank

I've got about a dozen rummynose tetras and 5 corys in there and the standard water params have been stable.

So far, I've done 2x 30% water changes over the course of about 1.5 months mainly to clear out some mulm and melting plants but that's about it. Right now, it's been almost 3 weeks and the standard water params look good.

I've heard so many mixed opinions on this so would love to hear your experiences!

 

[TwoTankAmin]

At least 50%/week. With a high light pressurized CO2 planted tank that can be twice a week. We often forget that there are two reasons we change water, The first is the obvious one, to replenish things which have been used up. But the second reason is to remove things that are accumulating which can become harmful beyond a given level.

Tanks are more unique the longer they have been established. I am talking about the water profile tight down to the most minute components. Consider that we measure ammonia in parts per million. While this is one of the things we don't want in any concentration our test kits can measure, there are other things that are needed and/or which contribute to the complete profile of what is in the water of any tank.

The presence of plants can magnify things and they most certainly alter them. They consume things and they produce things. And this is the case if they are healthy and having a positive effect on a tank or they are doing badly and dying which also effects what is in the water. In some planted tanks and tap water lacking some of what they need and having things they don't, we may have to add some form of fertilizers. The more light one has the faster plants grow and the more "food" they need.

And that is why it is a good idea to change water regularly in a planted tank. Clear water doesn't necessarily mean healthy water. You cannot see ammonia in water, you can not see a lot of what is dissolved in water, but it is there.

 

[CaptainBarnicles]

Ahem...what he said

 

[Essjay]

Standard tests measure just ammonia, nitrite, nitrate and pH. Some also measure GH and KH. There is a lot more in water than just these. Fish excrete more than just ammonia, for example.